Crash energy absorption assembly for a motor vehicle

ABSTRACT

The modular front end forms the front portion of a motor vehicle. The modular front end includes a bulkhead defining a plurality of integrally formed attachment mounts. A drive train assembly carrying at least an engine of the motor vehicle is attached to the bulkhead at the attachment mounts. A crash energy absorption assembly is attached to the attachment mounts on the bulkhead and generally extends around the drive train assembly. An apron assembly is attached to the bulkhead at the attachment mounts and is generally positioned above the drive train assembly and crash energy absorption assembly.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional PatentApplication Serial No. 60/329,802, filed Oct. 16, 2001, and entitled“Modular Front End For Passenger Cars And Light Trucks, Joining AnIntegrated Drive Train Module, Apron-Cum Energy Module And Crash EnergyManagement Module To An Integrated Structural Cowl”, the full disclosureof which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to motor vehicles, such aspassenger cars and light trucks. More particularly, the presentinvention relates generally to a multi-component front end for a motorvehicle, which advances the methods by which motor vehicles areassembled.

2. Description of Related Art

Currently, the front ends of most motor vehicles are built into thevehicle body one piece or component at a time. The installation ofliterally hundreds of different components in the motor vehicle frontend requires the manufacturer to maintain lengthy, complex, and costlyassembly lines as well as extensive tooling and fixtures. Thiscomplexity is due not only to the high number of parts involved, butalso the assembly methods currently used in the automotive industry andthe amount of on-line adjusting and repair that is often needed tocorrect assembly defects. Additionally, the well-known assembly lineprocess is highly labor intensive, again due mainly to the high numberof parts and assembly methods currently used in the automotive industry.

Typically, once a painted vehicle body comes to the finish assemblyline, hundreds of individual components are assembled to the vehiclebody. The numerous individual components are used to complete thesuspension system, steering and braking system, power train, coolingsystem, electrical system, etc. As stated, the individual componentscomprising these systems are typically added to the vehicle bodyone-by-one or in small subgroups to finish the assembly of the motorvehicle.

The large number of components required to assemble a motor vehiclerequires the assembly line to be extremely long and requires many peopleto accomplish numerous discreet tasks along the assembly line. Thismakes the process of motor vehicle assembly unnecessarily slow andcomplicated and adversely affects the quality and reliability of themotor vehicle when it is completed. Additionally, the confined spacewithin which the workers operate makes on-line service and repair tasksdifficult and even dangerous. The overall complexity of the currentsystem for assembling motor vehicles is unnecessarily slow and expensiveand there is considerable room for improvement.

SUMMARY OF THE INVENTION

The present invention applies the general concept of using modules orassemblies in the manufacturing of motor vehicles. The concepts andembodiments disclosed hereinafter may be applied to other industriesthat utilize the long-standing assembly line technique for producingfinished products, such as the aircraft, agricultural machinery, truckmanufacturing, and mining vehicle industries. Generally, the presentinvention is a motor vehicle comprising a vehicle body having apre-assembled, modular front end. The modular front end is comprised ofseveral sub-modules or sub-assemblies, as discussed hereinafter.

The modular front end is based on the concept of “functionallydecoupling” the several sub-modules or sub-assemblies from each other.In front end assembly techniques currently practiced in the art, thevarious elements or components of the front end are substantiallyinterconnected or related. In contrast, the modular front end of thepresent invention has the various sub-assemblies comprising the frontend substantially functionally isolated from one another. The separatefunctions of the sub-assemblies, which will be discussed hereinafter,are substantially independent from one another allowing any onesub-module or sub-assembly to be individually replaced without affectingthe other sub-modules or sub-assemblies. This allows the sub-modules orsub-assemblies to be comprised of smaller and lighter individualcomponents or parts, which is not easily possible in the “interrelated”front end structures generally found in the prior art. The use ofseparate and distinct sub-modules or sub-assemblies in the modular frontend allows the overall size of the modular front end to be reducedbecause the sub-assemblies may be compact tightly within the modularfront end. The smaller front end made possible by the modular front endof the present invention improves the overall driving and handlingcharacteristics of the motor vehicle. For example, the smaller front endis lower in profile than those currently known in the art, whichimproves the driver's view of the road and aids the driver in performingroutine vehicle operations such as parking, turning, etc.

Generally, the modular front end comprises a bulkhead having a pluralityof preferably integrally formed attachment mounts, a drive trainassembly attached to the bulkhead at the attachment mounts, a crashenergy absorption assembly attached to the bulkhead at the attachmentmounts and, further, an apron assembly attached to the bulkhead assemblyat the attachment mounts. The apron assembly may be at least partiallysupported in the vertical direction by the crash energy absorptionassembly. The drive train assembly, crash energy absorption assembly,and apron assembly are each preferably attached mechanically to thebulkhead.

The bulkhead is preferably a cast bulkhead comprising a plurality ofintegrally formed attachment mounts. The bulkhead may be cast fromaluminum alloy as a unitary body. The bulkhead may also be comprised ofa plurality of individually cast components. The bulkhead may beprovided as part of a bulkhead assembly. The bulkhead assembly maycomprise a cast bulkhead defining a plurality of integrally formedattachment mounts and at least one structural member of the motorvehicle attached to the bulkhead. The bulkhead assembly may furtherinclude one or more electrical components attached to the bulkhead.

The bulkhead may define at least one hollow cavity formed therein forincreasing strength and rigidity of the bulkhead. The at least onehollow cavity may be filled with a cast-in-place core, preferably analuminum foam core. The hollow cavity may also be filled with polymericfoam. The at least one structural member may comprise a pair of doorhinge pillars attached to attachment mounts located at opposite ends ofthe bulkhead. The at least one structural member may also comprise apair of rocker panels attached to a bottom end of the bulkhead oppositethe door hinge pillars. Additionally, the at least one structural membermay comprise a pair of windshield support pillars attached to a top endof the bulkhead. The at least one structural member may further comprisea windshield cross member attached to the top end of the bulkheadbetween the windshield support pillars.

The bulkhead may comprise a first side for facing an engine compartmentof the motor vehicle and a second side for facing a passengercompartment of the motor vehicle. A pair of hood hinges, which may eachinclude a hood lift assist mechanism, may be attached to attachmentmounts located on the first side of the bulkhead for supporting a hoodof the motor vehicle. The electrical component(s) is preferably attachedto the first side of the bulkhead, but may be attached to the secondside facing the passenger compartment. The electrical component(s) mayinclude, for example, a windshield wiper motor and/or an electricaljunction box.

The drive train assembly generally comprises a drive train support and apower train assembly attached to the drive train support. The drivetrain support comprises a pair of elongated support members that areconfigured for attachment, preferably by mechanical means, to a bulkheadof the motor vehicle. By mechanical attachment or means, it is meantthat mechanical fasteners, such as nuts and bolts, rivets, and the likeare preferably used to attach the various elements described in thisdisclosure, and may include rubber isolation mounts (i.e., bushings),where necessary, to minimize vibration between elements. The drive trainsupport further comprises a cross member interconnecting the supportmembers. The support members are further configured to support the powertrain assembly such that the power train assembly is cantilevered fromthe support members and bulkhead forward of the cross member.

The support members and cross member may be made of aluminum alloy. Thesupport members may be cast aluminum alloy support members. The crossmember may be an extruded aluminum alloy cross member. The supportmembers each comprise a top end and a bottom end. The cross memberpreferably connects the top ends of the support members. The crossmember may be connected mechanically to the support members.

In the modular front end, the power train assembly is attached to thesupport members such that the power train assembly is cantilevered fromthe support members and bulkhead forward of the cross member. Thesupport members may be attached mechanically to the bulkhead. Themechanical attachment may comprise at least one isolation mount fordampening vibration of the power train assembly. The power trainassembly may comprise an engine and transmission of the motor vehicle.The engine may be mechanically attached to the drive train support andcomprise at least one isolation mount for dampening vibration of theengine. The transmission may be mechanically attached to the drive trainsupport and comprise at least one isolation mount for dampeningvibration of the transmission. The drive train assembly may furthercomprise a steering gear of the motor vehicle attached to the bottomends of the support members and interconnecting the bottom ends of thesupport members. Further, the drive train assembly may comprise a brakeand suspension assembly for each front wheel of the motor vehicle. Thebrake and suspension assemblies are attached to the support members,respectively, and preferably the lower ends of the support members. Thebrake and suspension assemblies may each comprise a control armconnected to the respective support members, preferably mechanically.

The crash energy absorption assembly generally comprises an elongatedbumper beam, a pair brackets attached to the bumper beam, and a pair oftubes supported by the brackets. The tubes each have a first end and asecond end. The first ends of the tubes are supported by the brackets.The second ends of the tubes may be attached to the bulkhead at theattachment mounts. A crosstie may interconnect the brackets. The bumperbeam, brackets, and tubes may be made of aluminum alloy.

The bumper beam may define a substantially open cross section, which maybe at least partially, but preferably completely, filled with polymericfoam. The bumper beam may define a substantially Σ-shaped cross section.The substantially Σ-shaped cross section may comprise a rear wallconnected to substantially parallel top and bottom walls. The bracketsmay be attached to the bumper beam opposite the rear wall.

The tubes may be at least partially filled with polymeric foam. Thetubes may comprise a tube with a cross-sectional profile selected fromthe group consisting of a circle, a square, an oval, a rectangle, ahexagon, and a combination thereof The tubes may have differentcross-sectional profiles. The brackets are preferably attachedmechanically to the bumper beam. The brackets may define socketsconfigured to receive the first ends of the tubes. The tubes may besecured mechanically in the sockets. The bumper beam may define anoverall curved shape. In the modular front end, the second ends of thetubes are attached to the bulkhead at the attachment mounts. Thebrackets may be taper and flare brackets, which absorb impact energyusing the taper and flare principle known in the art. Alternatively, thebrackets may be conventional brackets and the tubes may be crush tubesfor absorbing crash energy during a collision.

The apron assembly generally comprises an apron and, preferably, atleast one engine accessory of the motor vehicle attached to the apron.The apron generally comprises a substantially C-shaped, unitary apronmember having a depending front portion and a substantially C-shapedapron rail attached to a top end of the apron member. The apron memberdefines at least one integrally formed accessory attachment mount formounting the at least one engine accessory of the motor vehicle. Theapron rail is attached to the top end of the apron member and isconfigured for attachment to the bulkhead. Preferably, the ends of theapron rail are attached to the bulkhead. The apron rail may beconfigured for mechanical attachment to the bulkhead The apron rail ispreferably attached mechanically to the apron member. The apron memberis preferably formed of molded plastic material and the apron rail ispreferably made of aluminum alloy. The apron rail may be a hydro-formedtube defining differing cross-sectional areas along its length, whichprovide mounting locations for various front end components of the motorvehicle such as the vehicle fenders. The at least one accessoryattachment mount may comprise a plurality of openings defined in thefront portion of the apron member.

The at least one engine accessory may be a radiator and cooling fanassembly and the accessory attachment mount may be an opening defined inthe front portion of the apron member. The radiator and cooling fan issupported in the opening. The at least one engine accessory may be anair conditioning condenser and the attachment mount may be a secondopening defined in the front portion of the apron member. The airconditioning condenser is supported in the second opening. Additionally,the at least one engine accessory may be a transmission oil cooler andthe accessory attachment mount may be a third opening defined in thefront portion of the apron member. The transmission oil cooler issupported in the third opening. Further, the at least one engineaccessory may be a battery and the accessory attachment mount may be anintegrally formed battery hold-down. The battery is supported in thebattery hold down. The apron assembly may further comprise fendersattached to the apron rail and/or headlights attached to the frontportion of the apron member. Other possible engine accessories includefluid reservoirs for the radiator and cooling assembly, windshield wiperfluid etc.

The present invention is also a method of assembling a modular front endfor a motor vehicle. The method comprises the steps of providing abulkhead having a plurality of attachment mounts; attaching a drivetrain assembly to the bulkhead at the attachment mounts; attaching acrash energy absorption assembly to the bulkhead at the attachmentmounts; and attaching an apron assembly to the bulkhead at theattachment mounts. The bulkhead may be pre-attached to the vehicle bodyand the various assemblies identified hereinabove assembled to thepre-attached bulkhead. Thus, the step of providing the bulkhead includesboth a separate, stand alone bulkhead that is to be attached to avehicle body, and a bulkhead that is pre-attached to a vehicle body.

The method may further comprise the step of casting the bulkhead as aunitary bulkhead. The attachment mounts are preferably formed integrallywith the unitary bulkhead. The bulkhead may be cast from aluminum alloy.The method may further comprise the step of attaching at least onestructural member of the motor vehicle to the bulkhead.

The bulkhead may comprise a first side for facing an engine compartmentof the motor vehicle and a second side for facing a passengercompartment of the motor vehicle. The method may comprise the step ofattaching at least one electrical component of the motor vehicle to thefirst side of the bulkhead. The drive train assembly, crash energyabsorption assembly, and apron assembly may be attached mechanically tothe attachment mounts located on the first side of the bulkhead.

The drive train assembly may comprise a drive train support and a powertrain assembly. The power train assembly may comprise an engine and atransmission of the motor vehicle attached to the drive train support.The step of attaching the drive train assembly to the bulkhead maycomprise attaching the drive train support to the bulkhead at theattachment mounts such that the power train assembly is cantileveredfrom the drive train support and bulkhead. The power train support maycomprise a pair of support members each having a top end and a bottomend and a cross member connecting the top ends of the support members.The method may further comprise the step of attaching a steering gear ofthe motor vehicle to the bottom ends of the support members tointerconnect the support members. The drive train assembly may furthercomprise a brake and suspension assembly for each front wheel of themotor vehicle. Further, the method may comprise the step of attachingthe brake and suspension assemblies to the support members,respectively.

The crash energy absorption assembly may comprise an elongated bumperbeam, a pair of brackets attached to the bumper beam, and a pair oftubes each having a first end and a second end. The first ends of thetubes may be supported by the brackets. The step of attaching the crashenergy absorption assembly to the bulkhead may comprise attaching thesecond ends of the tubes to attachment mounts preferably located on thefirst side of the bulkhead.

The apron assembly may be partially supported in the vertical directionby the crash energy absorption module. The apron assembly may comprisean apron member and at least one engine accessory of the motor vehicleattached to the apron member. The method may further comprise the stepof attaching the at least one engine accessory of the motor vehicle tothe apron member. The at least one engine accessory may be a radiatorand cooling fan assembly, an air conditioning condenser, a transmissionoil cooler, and/or a battery. Other possible engine accessories includefluid reservoirs for the radiator and cooling assembly, windshield wiperfluid etc. The apron member may be substantially C-shaped and have adepending front portion. The apron assembly may further comprise asubstantially C-shaped apron rail. The method may comprise the step ofattaching the apron rail to a top end of the apron member. The ends ofthe apron rail may be configured for connection to the bulkhead at theattachment mounts. The step of attaching the apron assembly to thebulkhead may comprise attaching the ends of the apron rail to thebulkhead at the attachment mounts. Furthermore, the method may comprisethe steps of attaching one or more fenders of the motor vehicle to theapron rail, and attaching headlights of the motor vehicle to the frontportion of the apron member.

Further details and advantages of the present invention will becomeapparent from the following detailed description when read inconjunction with the drawings, wherein like parts are designated withlike reference numerals throughout.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a motor vehicle having a modular frontend in accordance with the present invention;

FIG. 2 is a perspective view of the modular front end shown in FIG. 1;

FIG. 3 is a perspective view of a bulkhead assembly used in the modularfront end of FIGS. 1 and 2;

FIG. 4 is a perspective view of a bulkhead used in the bulkhead assemblyof FIG. 3 showing the passenger compartment facing side of the bulkhead;

FIG. 5 is a perspective view of the bulkhead used in the bulkheadassembly of FIG. 3 showing the engine compartment facing side of thebulkhead;

FIG. 6 is a perspective view of the bulkhead assembly generally showingthe engine compartment facing side of the bulkhead;

FIG. 7 is a perspective view of the bulkhead assembly generally showingthe passenger compartment facing side of the bulkhead;

FIG. 8 is a perspective view of a drive train assembly used in the inthe modular front end of FIGS. 1 and 2;

FIG. 9 is a side view of the drive train assembly of FIG. 8;

FIG. 10 is a perspective view of a drive train support used in the drivetrain assembly of FIG. 8;

FIG. 11 is a perspective view of the drive train support of FIG. 10generally viewed from the opposite or reverse side;

FIG. 12 is a perspective view of the drive train assembly of FIG. 8 withthe bulkhead removed and showing the various components of the drivetrain assembly;

FIG. 13 is a bottom view of the drive train assembly of FIG. 8;

FIG. 14 is a perspective view of a crash energy absorption assembly usedin the modular front end of FIGS. 1 and 2;

FIG. 15 is a second perspective view of the crash energy absorptionassembly used in the in the modular front end of FIGS. 1 and 2;

FIG. 16 is a perspective view of an apron assembly used in the in themodular front end of FIGS. 1 and 2;

FIG. 17 is a perspective view showing an apron of the apron assembly ofFIG. 16;

FIG. 18 is a perspective view of the apron assembly of FIG. 16 generallyviewed from the opposite or reverse side;

FIG. 19 is a perspective view of the apron assembly of FIG. 16 furthershowing a fender and headlights of the motor vehicle attached to theapron assembly;

FIG. 20 is a perspective view of the modular front end of FIGS. 1 and 2showing only the structural components of the various assemblies; and

FIG. 21 is a second perspective view of the modular front end shown inFIG. 20.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

For purposes of the description hereinafter, the terms “upper”, “lower”,“right”, “left”, “vertical”, “horizontal”, “top”, “bottom”, andderivatives thereof shall relate to the invention, as it is oriented inthe drawing figures. However, it is to be understood that the inventionmay assume various alternatives and step sequences, except whereexpressly specified to the contrary. It is also to be understood thatthe specific elements and processes illustrated in the drawings, anddescribed in the following specification, are simply exemplaryembodiments of the invention. Hence, specific dimensions and otherphysical characteristics related to the embodiments disclosed herein arenot to be considered alimiting.

Referring to FIGS. 1 and 2, a motor vehicle 1 comprising a modular frontend 10 in accordance with the present invention is shown. Only the frontportion of the motor vehicle 1 is shown, but the remainder of the motorvehicle 1 is conventional. The modular front end 10 forms the completefront portion of the motor vehicle 1. Once assembled, the modular frontend 10 may be attached to the body of the motor vehicle 1 substantiallyin one step, significantly increasing the efficiency of assembling themotor vehicle 1. The modular front end 10 preferably arrivespre-assembled to the assembly line where it is joined to the body of themotor vehicle 1. The modular front end 10 allows the length of theassembly line to be reduced because the large number of parts typicallyfound in the front end of the motor vehicle 1 is now consolidated intoseveral sub-modules or sub-assemblies, each of which is described indetail hereinafter. The modular front end 10 also reduces the assemblyequipment and the number of workers required to manufacture the motorvehicle 1. Further, the individual assemblies comprising the modularfront end 10 may be tested for performance prior to their installationin the modular front end 10, which improves the overall quality of themotor vehicle 1.

The modular front end 10 is generally comprised of four (4) separatesub-modules or assemblies. The four distinct modules include a bulkheadassembly 100, a drive train assembly 200, a crash energy absorptionassembly 300, and an apron assembly 400. The bulkhead assembly 100generally provides the structural support for mounting and supportingthe other assemblies 200, 300, 400. The drive train assembly 200 isdirectly attached to the bulkhead assembly 100 The crash energyabsorption assembly 300 is positioned generally around the lower portionof the drive train assembly 200 and is also directly attached to thebulkhead assembly 100. The apron assembly 400 is generally positioned ontop of the drive train assembly 200 and the crash energy absorptionassembly 300, and generally surrounds the drive train assembly 200. Eachof the assemblies 100-400 will be discussed in detail hereinafter, aswell as a preferred method of assembling the modular front end 10 of themotor vehicle 1.

The various assemblies 100-400 are independent of one another or“functionally decoupled” from one another and are generally interrelatedby their connection to the bulkhead assembly 100, which provides thestructural support for the other assemblies 200-400. The bulkheadassembly 100 may be provided separately from or pre-attached to the bodyof the motor vehicle 1. Thus, the modular front end 10 may bepre-assembled and attached to the body of the motor vehicle 1, or thebulkhead assembly 100 may be pre-attached to the body of the motorvehicle 1 and the other assemblies 200-400 then attached to the bulkheadassembly 100.

Referring to FIGS. 1-7, the bulkhead assembly 100 is generally comprisedof a cast, preferably unitary, bulkhead 102 and a plurality ofcomponents or parts, such as structural members of the motor vehicle,attached to the bulkhead 102. The bulkhead 102 serves as the basestructural component that the supports the drive train assembly 200, thecrash energy absorption assembly 300, and the apron assembly 400.

The unitary bulkhead 102 is preferably an ultra-large casting ofaluminum or aluminum alloy or a similar material such as magnesiumalloy, or formed of fiber reinforced polymer composite materials. Thebulkhead 102 is a unitary bulkhead that replaces the typical 10 to 15stamped steel parts typically used in existing bulkhead designs. The useof aluminum and aluminum alloys reduces the weight of bulkhead 102 incomparison to traditional bulkhead designs. The bulkhead 102 may also beformed of multiple cast components, each preferably cast from aluminumalloy, and joined together by means customary in the art.

The bulkhead 102 is preferably cast with one or more hollow cavities 104formed therein for increasing the strength and rigidity of the bulkhead102. The hollow cavity 104 may be filled with a cast-in-place core orpolymeric foam 106. The cast-in-place core 106 is preferably aluminumfoam. When polymeric foam is used, the polymeric foam 106 is filled intothe hollow cavity 104 after casting. The cast-in-place aluminum foamcore or polymeric foam 106 increases the strength and stiffness of thesystem but also reduces the chance of internal corrosion in the bulkhead102. The bulkhead 102 is generally rectangular shaped and has oppositelateral ends 108, 110, and top and bottom ends 112, 114. The top end 112of the bulkhead 102 may define a longitudinally extending opening 116,which may be used to route heating and ventilating ducting as well asproviding a drainage conduit for water flowing off the windshield of themotor vehicle 1. The rectangular shaped bulkhead 102 has a first side118 and a second side 120. The first side 118 faces an enginecompartment 122 defined by the modular front end 10, and the second side120 faces a passenger compartment 124 of the motor vehicle 1.

The bulkhead 102 is preferably cast to have a plurality of integrallyformed attachment mounts 126. The attachment mounts 126 providelocations for attaching the drive train assembly 200, the crash energyabsorption assembly 300, and the apron assembly 400 to the bulkhead 102.Additionally, the attachment mounts 126 provide locations for attachingadditional components of the bulkhead assembly 100 to the bulkhead 102.These additional components, discussed hereinafter, may also be attacheddirectly to the top and bottom ends 112, 114 and first and/or secondsides 118, 120 of the bulkhead 102. The integral attachment mounts 126generally provide specific locations for mounting the various assemblies200, 300, 400.

The bulkhead assembly 100 further includes additional parts orcomponents, such as structural members 128 or electrical components 130,of the motor vehicle 1. The structural members 128 may include, but arenot limited to, a pair of door hinge pillars 132, 134, a pair of rockerpanels 136, 138, a pair of windshield support pillars 140, 142, and awindshield cross member 144, each mounted to the bulkhead 102. Theelectrical components 130 may include, but are not limited to, anelectrical junction box 146 and a windshield wiper motor 148.

The pair of door hinge pillars 132, 134 is mounted to the opposite ends108, 110 of the bulkhead 102. The door hinge pillars 132, 134 aremounted to four (4) attachment mounts 126 dp located on each of theopposite ends 108, 110 of the bulkhead 110. The door hinge pillars 132,134 provide mounting locations for mounting the doors of the motorvehicle 1.

The pair of rocker panels 136, 138 is mounted the bulkhead 102 generallyopposite from the door hinge pillars 132, 134. The rocker panels 136,138 are located and attached to the bottom end 114 of the bulkhead 102.The rocker panels 102 are, in turn, connected to the body of the motorvehicle 1 in a conventional manner.

The pair of windshield support pillars 140, 142 is mounted at the topend 112 of the bulkhead 102. Preferably, the windshield support pillars140, 142 are mounted to two integral attachment mounts 126 wp located atthe top end 112 of the bulkhead 102. The windshield support pillars 140,142 are used to support a windshield 150 of the motor vehicle 1, asshown in FIG. 3. The windshield cross member 144 is also mounted at thetop end 112 of the bulkhead 102 between the windshield support pillars140, 142 to further support the windshield 150.

A pair of hood hinges 152 may be mounted to two (2) attachment mounts126 hh located on the first side 118 of the bulkhead 102. The hoodhinges 152 support a hood (not shown) of the motor vehicle 1 in aconventional manner, and may each include hood-lift assist mechanisms (ie., air cylinders or springs), which are conventional in the art.

As stated previously, various electrical components 130 of the motorvehicle 1 may be attached to the bulkhead 102. In FIG. 3, two exemplaryelectrical components 130 of the motor vehicle 1 are shown attached tothe first side 118 of the bulkhead 102. The electrical components 130shown include the electrical junction box 146 and the windshield wipermotor 148 of the motor vehicle 1. Additional attachment mounts 126formed on the first side 118 of the bulkhead 126 are used as attachmentpoints for the drive train assembly 200, crash energy absorptionassembly 300, and apron assembly 400, as discussed hereinafter.

Referring to FIGS. 1-3 and 8-13, the drive train assembly 200 isattached to the first side 118 of the bulkhead 102 at four (4) specificattachment mounts 126 a, 126 b, 126 c, 126 d formed on the first side118, which are adapted to support the weight of the drive train assembly200. The drive train assembly 200 is generally comprised of a drivetrain support 202 and a power train assembly 204 attached to the drivetrain support 202. The drive train support 202 is comprised of a pair ofelongated support members 206, 208, which are preferably mechanicallyattached to the bulkhead 102 at the four (4) specific attachment mounts126 a-d on the first side 118 of the bulkhead 102. Each of the supportmembers 206, 208 has two (2) points of connection 209 to the bulkhead102. Preferably, the points of connection 209 between the supportmembers 206, 208 and the attachment mounts 126 a-d on the bulkhead 102each include a rubber isolation bushing or mount 211 for reducingvibration between the bulkhead 102 and the drive train assembly 200.These attachments are designed to be in orthogonal directions. Thesupport members 206, 208 are preferably cast aluminum or aluminum alloysupport members. However, the support members 206, 208 may be cast fromother similar metals such as magnesium and alloys thereof or ferrouscontaining metals and even non-metallic materials such as fiberreinforced polymer composite materials.

A cross member 210 interconnects the support members 206, 208. The crossmember 210 is preferably mechanically connected to the support members206, 208. As used in this disclosure, the terms “mechanically”,“mechanically connected”, or “mechanical means” and similar phrases areintended to mean the use of mechanical fasteners such as nuts, bolts,rivets, and the like, and their substantial equivalents, and may includethe use of vibration isolation joints such as rubber bushings or similarresilient structures as necessary to reduce vibration and noise. Thecross member 210 is preferably an extruded aluminum alloy cross member,but may be a cast article and may be made of any of the materials listedpreviously in connection with the support members 206, 208. The supportmembers each have a top or upper end 212 and a bottom or lower end 214.The cross member 210 preferably connects the top or upper ends 212 ofthe support members 206, 208.

The power train assembly 204 is supported entirely by the supportmembers 206, 208 and bulkhead 102 in the modular front end 10. There isat least one and, preferably, multiple points of connection between thepower train assembly 204 and drive train support 202, as discussedhereinafter. As indicated previously, there are preferably four (4)points of connection between the drive train support 202 and thebulkhead 102 at attachment mounts 126 a-d. The support members 206, 208are attached to the bulkhead 102 and generally extend vertically alongthe bulkhead 102. Thus, the power train assembly 204 is cantileveredfrom the support members 206, 208 and the bulkhead 102 in the modularfront end 10. By “cantilevered” it is meant that the center of gravityof the power train assembly 204 is positioned outward from the bulkhead102 and drive train support 202. The attachment mounts 126 a-d at thetop and bottom ends 112, 114 of the bulkhead 102 provide the verticalsupport for the power train assembly 204. The attachment mounts 126 a,126 b located at the bottom end 114 of the bulkhead 102 are horizontallyoriented so that the power train assembly 204 is supported in twoplanes, horizontal and vertical.

In summary, the power train assembly 204 is substantially supported in a“cantilevered” fashion by a substantially vertically oriented powertrain support 202, which is connected to the bulkhead 102 mechanically.This is in contrast to typical engine support arrangements currentlyused in the automotive industry in which a horizontally extending enginecradle supports the engine of the motor vehicle. The engine cradle inknown engine support arrangements is rigidly connected to the frame ofthe motor vehicle and supports the engine from underneath.

The power train assembly 204 generally includes an engine 216 and atransmission 218 of the motor vehicle 1. The engine 216 has numerouscomponents associated therewith, such as an engine manifold 220 and anengine exhaust 222. In this disclosure, the term “engine” 204 is meantto include the power generating unit of the motor vehicle 1 as well asany accessories directly connected thereto necessary for generatingpower for the motor vehicle 1. The engine 216 and transmission 218 aremechanically attached to the support members 206, 208 at multipleconnection or mounting points 219 as best shown FIGS. 11 and 12. Themounting points 219 may be vibration-isolated through the use of aplurality of rubber isolation bushings or mounts 221, again as bestshown in FIGS. 11 and 12.

Additional components of the modular front end 10 may be supported onthe drive train support 202, either directly or indirectly. For example,the drive train assembly 200 may further comprise a steering gear 224 ofthe motor vehicle 1. The steering gear 224 of the motor vehicle 1 ishoused within a housing 225. The steering gear 224 is attached to thebottom ends 214 of the support members 206, 208, with the housing 225interconnecting the support members 206, 208 at the lower end 214 ofeach of the support members 206, 208. The support members 206, 208,cross member 210, and steering gear 224 and housing 225 form a solidfour (4) sided frame for supporting the power train assembly 204. Thesteering gear 224 is conventional in the art and is configured to beconnected to the steering column (not shown) of the motor vehicle 1

The motor vehicle 1 comprises two front wheels 226, 228. A brake andsuspension assembly 230 is associated with each of the front wheels 226,228 to interconnect the front wheels 226, 228 to the drive trainassembly 200 and, more particularly, the drive train support 202. Thebrake and suspension assembly 230 generally includes the componentsnecessary to apply braking to the front wheels 226, 228, andinterconnect the front wheels 226, 228 to the drive train assembly 200.The front wheels 226, 228 are respectively connected to two power trainshafts 232, 234, which extend outward from the transmission 218 andprovide power to the front wheels 226, 228.

The brake and suspension assemblies 230 each include a knuckle 236, abraking assembly 238 connected to the knuckle 236, and a lower controlarm 240 connected to the knuckle 236. A sway bar 242 may interconnectthe two (2) brake and suspension assemblies 230. The knuckle 236 foreach of the assemblies 230 is conventional and may be connected by ashock absorber and spring assembly 244 to the top end 212 of the supportmembers 206, 208 in each assembly 230. The braking assembly 238 (i.e.,rotor, caliper etc.) is also conventional and is supported by theknuckle 236 in each of the assemblies 230. The knuckle 236 in eachassembly 230 is connected to the lower end 214 of the respective supportmembers 206, 208 by the respective lower control arms 240. The lowercontrol arms 240 are connected to the respective support members 206,208 mechanically, such as with bushings 246. The bushings 246 may berubber isolation bushings or mounts as are known in the art. The lowercontrol arm 240 shown on the passenger's or left side of the drive trainassembly 200 (top portion of FIG. 13) is the subject matter of U.S.patent application Ser. No. 10/271,449 filed the same day as thisapplication, Oct. 16, 2002, and entitled “Control Arm For Motor VehicleSuspension System”, and naming Dinesh C. Seksaria and John W. Cobes asinventors. The disclosure of the foregoing United States PatentApplication is incorporated fully herein by reference.

The drive train assembly 200 contains each of the components required tomake the motor vehicle 1 move, stop, and steer. The drive train support202 is specifically adapted to support the engine 216 and transmission218 in the vertical direction, such that the engine 216 and transmission218 are cantilevered from the bulkhead 102, as defined previously. Thebulkhead 102 generally separates the engine compartment 122 from thepassenger compartment 124 in the motor vehicle 1. The engine 216 andtransmission 218 are now located directly in front of the bulkhead 102providing an extra layer of protection for occupants of the passengercompartment 124 in the event of a front end collision. Additionally, theengine 216, transmission 218, steering gear 224, and brake andsuspension assemblies 230 for the two front wheels 226, 228 are all nowcompacted tightly within a single sub-assembly, which may be pre-testedas a unit before assembly to the motor vehicle 1 The compact nature ofthe drive train assembly 200 also provides a more direct and shorterpath for exhaust gases from the engine 216, which improves performanceand fuel efficiency of the engine 216 while reducing emissions. Thecompact form of the drive train assembly 200 frees up additional spacefor expanding the passenger compartment 124 of the motor vehicle 1.Furthermore, the weight of the engine 216 and transmission 218 iscentered substantially directly over the wheel axis of the front wheels226, 228, which will improve the traction and handling of the motorvehicle 1.

Referring to FIGS. 1-3 and 14 and 15, the crash energy absorptionassembly 300 is attached to the first side 118 of the bulkhead 102 attwo attachment mounts 126 e, 126 f generally located laterally outsideof the attachment mounts 126 a-d for the drive train assembly 200. Thecrash energy absorption assembly 300 is preferably fixedly mounted tothe two attachment mounts 126 e, 126 f. The crash energy absorptionassembly 300 is used to absorb impact energy during a collisioninvolving the modular front end 10 of the motor vehicle 1 and to managethe energy to avoid injury to occupants of the passenger compartment124. The crash energy absorption assembly 300 is pre-assembled andattached to the bulkhead 102 in a similar manner to the drive trainassembly 200 discussed hereinabove.

The crash energy absorption assembly 300 is generally comprised of anelongated bumper beam 302, a pair of brackets 304, 306, and a pair ofelongated tubes 308, 310. The brackets 304, 306 are attached to thebumper beam 302, preferably by mechanical means. The brackets 304, 306are preferably taper and flare brackets. In FIGS. 14 and 15 only theright side or driver's side bracket 304 is illustrated as a taper andflare bracket. The left or passenger's side bracket 306 (top of FIGS. 14and 15) is illustrated as a conventional bracket. The term “brackets304, 306” is intended to represent both taper and flare and conventionalbrackets in this disclosure. A suitable taper and flare bracketarrangement for the brackets 304, 306 is disclosed in U.S. patentapplication Ser. No. 09/932,673 to Summe et al., which is assigned tothe common Assignee of this application, and is incorporated herein byreference in its entirety. The brackets 304, 306, when provided as taperand flare brackets, perform the function of tapering and flaring thetubes 308, 310 from the bumper beam 302. When the brackets 304, 306 areconventional brackets, the elongated tubes 308, 310 are preferably crushtubes, which accommodate impact energy involving the modular front end10 and the crash energy absorption assembly 300.

The tubes 308, 310 each have a first end 312 and a second end 314. Thefirst ends 312 of the tubes 308, 310 are supported by the brackets 304,306. The brackets 304, 306 each define a socket 316 for receiving andsupporting the tubes 308, 310. The first ends 312 of the tubes 308, 310are received and secured in the sockets 316 defined by the brackets 304,306, preferably by mechanical means, which may include an interferencefit. The second ends 314 of the tubes 308, 310 are configured forconnection to the two outer attachment mounts 126 e, 126 f formed on thefirst side 118 of the bulkhead 102. The tubes 308, 310 may be made ofaluminum or aluminum alloy such as 7003 T6, 6082 T6 aluminum alloys,other aluminum alloys such as 6061 T6 aluminum alloy, high strengthsteels, or non-metallic materials such as fiber reinforced polymercomposite materials. Any of the 6XXX and 7XXX aluminum alloys asdesignated by the Aluminum Association may be used for the tubes 308,310.

The tubes 308, 310 may be at least partially or fully filled withpolymeric foam 318. Preferably, the polymeric foam 318 is located atleast within the second ends 314 of the tubes 308, 310. The tubes 308,310 have hollow cross sectional profiles for receiving the polymericfoam 318. The tubes 308, 310 may have different cross sectionalprofiles, but it is generally preferred that the tubes 308, 310 have thesame cross sectional profiles. As shown in FIGS. 14 and 15, the crosssectional profiles for the tubes 308, 310 may be oval or a polygonalshape such as a double hexagon, “figure-8” profile. Other possible crosssectional profiles for the tubes 308, 310 include circular, square,rectangular, and combinations of these profiles and the oval andhexagonal profiles illustrated. Oval or circular cross sectionalprofiles are preferred for use with taper and flare brackets, while anyof the cross sectional profiles indicated hereinabove may be used whenthe tubes 308, 310 are provided as crush tubes, which are used withtraditional, for example stamped steel, brackets.

As stated previously, the brackets 304, 306 may be both taper and flarebrackets, or both conventional brackets. In FIGS. 14 and 15, the left(passenger's) side bracket 306 is illustrated as a conventional bracketwhile the right or driver's side bracket 302 is illustrated as a taperand flare bracket. When the brackets 304, 306 are conventional (i.e.,can be made of any specified material but the design is conventional),the tubes 308, 310 are provided as crush tubes that absorb crash energyby crushing or collapsing during a collision involving the modular frontend 10.

The bumper beam 302 has a generally curved shape. Since the bumper beam302 has a generally curved shape, front impact forces on the bumper beam302 will generate a significant cross spreading force. To counter this,the brackets 304, 306 are connected by a crosstie 320, which manages thetransverse spreading force. The crosstie 320 interconnects the brackets304, 306 for stability. The bumper beam 302, brackets 304, 306, andtubes 308, 310 are preferably each made of aluminum or aluminum alloy.The bumper beam 302 is preferably made of 6013 T6 or 6061 T6 aluminumsheet that is roll formed into an open cross sectional shape. The bumperbeam 302 may be made of an aluminum alloy selected from the 6XXX or 7XXXseries aluminum alloys. Generally, the bumper beam 302 defines an opencross sectional shape that is at least partially, preferably completely,filled with polymeric foam 322. The bumper beam 302 may also be made ofother aluminum alloys such as 7003 T6 or 6082 T6 aluminum alloys, orother alloys selected from the 6XXX or 7XXX series aluminum alloys, orbe made from high strength steel sheet. The bumper beam 302 preferablydefines a substantially Σ-shaped open cross section. The substantiallyΣ-shaped cross section comprises a rear wall 324 connected tosubstantially parallel top and bottom walls 326, 328. A suitable bumperbeam 302 having the Σ-shaped open cross section described hereinabove isfound in U.S. Pat. No. 6,308,999 to Tan et al. assigned to Alcoa Inc.,Pittsburgh, Pa., the common assignee of this application, and isincorporated herein in its entirety.

The brackets 304, 306 are preferably aluminum alloy extrusions and arepreferably taper and flare brackets as indicated previously. Suitablealuminum alloys for the taper and flare brackets include 7003 T6 and6082 T6 aluminum alloys. Again, however, the taper and flare brackets304, 306 may be made of an aluminum alloy selected from the 6XXX or 7XXXseries aluminum alloys. The brackets 304, 306 may also be made fromother materials such as high strength steel and non-metallic compositematerials such as polymer fibers such as carbon, glass, or arimid. Thebrackets 304, 306 are preferably mechanically attached to the bumperbeam 302 opposite the rear wall 324 in the Σ-shaped cross section of thebumper beam 302.

The crash energy absorption assembly 300 is provided as a pre-assembledunit for attachment to the bulkhead 302 in a similar manner to the drivetrain assembly 200 discussed previously. The use of aluminum or aluminumalloys in the components of the crash energy absorption assembly 300reduces the weight of the assembly 300 without sacrificing the energyabsorbing requirements of the assembly 300. Further, the positioning ofthe crash energy absorption assembly 300 generally around the drivetrain assembly 200 enhances the overall compactness of the modular frontend 10 of the present invention.

Referring to FIGS. 1-3 and 16-19, the apron assembly 400 is generallypositioned on top of the drive train assembly 200 and the crash energyabsorption assembly 300. The apron assembly 400 is pre-assembled andattached to the bulkhead 102 in a similar manner to the drive trainassembly 200 and crash energy absorption assembly 300 discussedpreviously. The apron assembly 400 generally extends around thecircumference of the engine compartment 122 defined by the modular frontend 10. The apron assembly 400 generally collects the miscellaneousengine accessories of the motor vehicle 1 and provides convenientlocations for mounting these accessories.

The apron assembly 400 is generally comprised of a unitary apron member402 having a depending front portion 404 and an apron rail 406 attachedto a top end of the apron member 402. The apron member 402 issubstantially C-shaped. The apron member 402 preferably defines aplurality of integrally formed accessory attachment mounts 408. Theapron 406 rail is also substantially C-shaped and is attached to the topend of the apron member 402. The apron rail 406 has two ends 410, 412configured for attachment to the bulkhead 102. In particular, the ends410, 412 are configured for connection to two (2) attachment mounts 126g, 126 h located adjacent the top end 112 of the bulkhead 102. Theconnections between the ends 410, 412 and the attachment mounts 126 g,126 h are preferably made by mechanical fasteners.

The apron member 402 is preferably a unitary member made of moldedplastic having the accessory attachment mounts 408 integrally formedtherewith. The apron rail 406 is preferably a one-piece, aluminum, andpreferably hydro-formed rail having differing cross sections along itslength and is attached to the apron member 402 mechanically. Thediffering cross sections provide additional locations for mounting frontend accessories used in the modular front end 10. The accessoryattachment mounts 408 may include integrally formed mounting points oropenings defined in the apron member 402 for supporting various frontend accessories

As stated, the apron assembly 400 generally collects the miscellaneousfront end engine accessories of the motor vehicle 1, which otherwisemust be individually assembled to the front end of the motor vehicle 1.Examples of such accessories include, but are not limited to, theradiator, coolant overflow bottle, transmission oil cooler, airconditioner condenser, fans, headlights, horn, battery, electrical fusebox, integral wire harnesses, windshield wiper washer fluid bottle, andair pump, etc. Several of the larger and more complex front end engineaccessories will be discussed hereinafter. The smaller front endaccessories, such as the coolant overflow bottle and windshield wiperwasher fluid bottle (not shown), easily attach to the apron member 402at the accessory attachment mounts 408 by mechanical fasteners, as willbe appreciated by those skilled in the art.

The front portion 404 of the apron member 402 defines a plurality ofopenings, hereinafter identified as first opening 414, second opening416, and third opening 418. The first opening 414 is formed centrally inthe front portion 404 and supports a radiator and cooling fan assembly420. The radiator and cooling fan assembly 420 is supported in the firstopening 414 by conventional means, such as mechanical fasteners. Thesecond opening 416 is defined adjacent the first opening 414 andsupports an air conditioning condenser 422 of the motor vehicle 1. Thethird opening 422 is defined on the other side of the first opening 414and supports a transmission oil cooler 424. The air conditioningcondenser 422, and transmission oil cooler 424 may be fixed in therespective second and third openings 416, 418 by conventional means(i.e., mechanical fasteners).

The apron member 402 further comprises an integrally formed batteryhold-down 426 for supporting a battery 426 of the motor vehicle 1. Thebattery 428 may be supported in the battery hold-down 426 by meansconventional in the art, such as straps and mechanical fasteners.

The apron assembly 400 provides a lightweight structure for collectingand supporting the miscellaneous front end accessories required for themotor vehicle 1. The apron assembly 400 is pre-assembled in a similarmanner to the drive train assembly 200 and the crash energy absorptionassembly 300. Each of the accessories attached to the apron member 402may be pretested prior to the apron assembly 400 being attached to thebulkhead 102. A similar procedure may be followed for the power trainassembly 204, steering and braking assembly 224, and axle assembly 240in the drive train assembly 200.

Furthermore, the apron assembly 400, particularly the apron rail 406,provides a convenient mounting structure for fenders 430 and other frontend components of the motor vehicle 1, as indicated previously.Additionally, headlights 432 of the motor vehicle 1 may be attached tothe front portion 404 of the apron member 402, which provides aconvenient location for supporting the headlights 432 of the motorvehicle 1. The fenders 430 and headlights 432 may be attached to theapron assembly 400 by conventional means (i.e., mechanical fasteners andthe like).

With the respective “modular” sub-assemblies 100-400 now described, amethod of assembling the modular front end 10 for attachment to themotor vehicle 1 will now be discussed with reference to FIGS. 1-21. Themethod of assembling the modular front end 10 generally begins withproviding the bulkhead assembly 100 having the structural members 128and electrical components 130 pre-attached thereto. The bulkhead 102 ofthe bulkhead assembly 100 provides the main structural member forsupporting each of the pre-assembled sub-assemblies 200-400 to follow.The bulkhead 102 may be provided separate from the body of the motorvehicle 1, or pre-attached to the body of the motor vehicle 1. Thevarious assemblies 200-400 may then be mounted to the pre-attachedbulkhead 102.

Next, the drive train assembly 200 is attached to the bulkhead 102 atthe four (4) drive train assembly attachment mounts 126 a-d located onthe first side 118 of the bulkhead 102. FIGS. 20 and 21 show the“structural elements” of the respective assemblies 100-400, with all“accessories” omitted for clarity in showing the mounting connectionsfor the drive train assembly 200, crash energy absorption assembly 300,and apron assembly 400. As described previously, the drive train support202 is affixed directly to the bulkhead 102. The power train assembly204, which generally comprises the engine 216 and transmission 218 ofthe motor vehicle 1, is cantilevered from the drive train support 202and bulkhead 102. The drive train assembly 200, as discussed previouslyis provided pre-assembled, with the power train assembly 204pre-attached to the drive train support 202 and the engine 216 andtransmission 218 pre-tested. The steering gear 224, which is connectedto the steering column of the motor vehicle 1, interconnects the lowerends 214 of the support members 206, 208 to form a solid box framestructure, as described previously. The brake and suspensions assemblies230 may be connected to the drive train support 202 in the mannerdescribed previously and pre-tested for function.

Once the drive train support 202 and pre-tested power train assembly 204are attached to the bulkhead 102, the crash energy absorption assembly300 may be attached to the bulkhead 102 at the attachment mounts 126 e,126 f, which are generally located outside of the drive train support202 attachment mounts 126 a-d used to support the drive train assembly200. The crash energy absorption assembly 300 is provided pre-assembledsuch that it is only necessary to attach the second ends 314 of thetubes 308, 310 to their corresponding attachment mounts 126 e, 126 f onthe first side 118 of the bulkhead 102.

With the drive train assembly 200 and the crash energy absorptionassembly 300 attached to the bulkhead 102, the apron assembly 400 may beattached to the bulkhead 102. The apron assembly 400 is attached to thebulkhead 102 by affixing the ends 410, 412 of the apron rail 406 at theapron assembly attachment mounts 126 g, 126 h generally located adjacentthe top end 112 of the bulkhead 102. The apron member 402 is partiallysupported in the vertical direction by the tubes 308, 310. Inparticular, a bottom end of the front portion 404 of the apron member402 rests on the tubes 308, 310 to provide vertical support for theapron assembly 400. The front portion 404 of the apron member 402 may beattached to the crosstie 320 connecting the brackets 304, 306 in thecrash energy absorption assembly 300. An adhesive may be used betweenthe bottom end of the front portion 404 of the apron member 402 and thesurfaces of the tubes 308, 310 to further secure the apron assembly 400to the crash energy absorption assembly 400. All attachments between thedrive train assembly 200, crash energy absorption assembly 300, andapron assembly 400 and the bulkhead 102 are preferably made withmechanical fasteners. Rubber bushings or mounts as discussed previouslymay be used in the connections between the drive train assembly 200 andthe bulkhead 102 to isolate these assemblies and minimize vibration asindicated previously.

In an alternative method of assembly, the apron assembly 400 may beattached first to the crash energy absorption assembly 300. This“combined” assembly (crash energy absorption assembly 300 and apronassembly 400) may then be attached as a unit to the bulkhead 102. Thecombined crash energy absorption assembly 300 and apron assembly 400 isthen attached to the bulkhead 102 in the manner described previously.Once again, the bulkhead 102 may be detached from or pre-attached to thebody of the motor vehicle 1.

The modular front end of the present invention results in higher qualitymotor vehicles and reduced costs to the manufacturer. Motor vehicleassembly lines may be shortened because the “sub-modules” orsub-assemblies described hereinabove collect numerous individual partsthat previously had to be individually assembled to the motor vehicle.Accordingly, an increased number of car bodies may be put through theassembly line in a given period of time. The modular front end alsoreduces the mass of the motor vehicle, which improves performance andthe fuel efficiency of the motor vehicle. Additionally, the modularfront end preferably uses mechanical fasteners at all connection pointsrather than metallurgical joints, which reduces production time andcost. In general, the modular front end of the present inventionimproves the speed and quality at which motor vehicles are constructed.

1. A crash energy absorption assembly for a motor vehicle having astructural bulkhead with a plurality of integrally formed attachmentmounts, said crash energy absorption assembly comprising: an elongatedbumper beam; a pair of brackets attached to the bumper beam; and a pairof metallic energy absorbing tubes each having a first end and a secondend, a substantially constant wall thickness and a substantially uniformcross-sectional area throughout its length, wherein the first ends ofthe tubes are supported by the brackets so as to be directly connectedto the bumper beam and each of the second ends of the tubes are attachedto one of said plurality of integrally formed attachment mounts, inorder that said crash energy absorption assembly is supported by saidbulkhead of the motor vehicle.
 2. The crash energy absorption assemblyof claim 1, further comprising a crosstie interconnecting the brackets.3. The crash energy absorption assembly of claim 1, wherein the bracketsare taper and flare brackets.
 4. The crash energy absorption assembly ofclaim 1, wherein the tubes are crush tubes.
 5. The crash energyabsorption assembly of claim 1, wherein the bumper beam, brackets, andtubes are made of aluminum alloy.
 6. The crash energy absorptionassembly of claim 1, wherein the bumper beam defines a substantiallyopen cross section at least partially filled with polymeric foam.
 7. Thecrash energy absorption assembly of claim 6, wherein the bumper beamdefines a substantially Σ-shaped cross section, the substantiallyΣ-shaped cross section comprising a rear wall connected to substantiallyparallel top and bottom walls.
 8. The crash energy absorption assemblyof claim 7, wherein the brackets are attached to the bumper beamopposite the rear wall.
 9. The crash energy absorption assembly of claim1, wherein the tubes are at least partially filled with polymeric foam.10. The crash energy absorption assembly of claim 1, wherein the tubeseach comprise a cross sectional profile selected from the groupconsisting of a circle, a square, an oval, a rectangle, and a hexagon.11. The crash energy absorption assembly of claim 1, wherein thebrackets are attached mechanically to the bumper beam.
 12. The crashenergy absorption assembly of claim 1, wherein the brackets definesockets for receiving the first ends of the tubes, and wherein the tubesare supported in the sockets.
 13. The crash energy absorption assemblyof claim 1, wherein the bumper beam defines a curved shape.
 14. A crashenergy absorption assembly for a motor vehicle having a bulkhead with aplurality of integrally formed attachment mounts, the crash energyabsorption assembly comprising: an elongated bumper beam defining asubstantially open cross section at least partially filled withpolymeric foam; a pair of taper and flare brackets attached to thebumper beam; a crosstie interconnecting the brackets; and a pair ofmetallic energy absorbing tubes each having a first end and a secondend, a substantially constant wall thickness and a substantially uniformcross-sectional area throughout its length, wherein the first ends ofthe tubes are supported by the brackets so as to be directly connectedto the bumper beam, and each of the second ends of the tubes areattached to one of said plurality of integrally formed attachmentmounts, in order that said crash energy absorption assembly is supportedby the bulkhead, the tubes at least partially filled with polymericfoam.
 15. The crash energy absorption assembly of claim 14, wherein thebumper beam defines a substantially Σ-shaped cross section, thesubstantially Σ-shaped cross section comprising a rear wall connected tosubstantially parallel top and bottom walls.
 16. The crash energyabsorption assembly of claim 15, wherein the brackets are attached tothe bumper beam opposite the rear wall.
 17. The crash energy absorptionassembly of claim 14, wherein the bumper beam, brackets, crosstie, andtubes are made of aluminum alloy.
 18. A method of assembling a crashenergy absorption assembly for a motor vehicle, comprising the steps of:providing an elongated bumper beam; attaching a pair of brackets to thebumper beam, the brackets defining sockets therein; providing a pair ofmetallic energy absorbing tubes each having a first end and a secondend, a substantially constant wall thickness and a substantially uniformcross-sectional area through its length; inserting and securing thefirst ends of the tubes in the sockets, the sockets configured toreceive and support the first ends of the tubes so that the tubes aredirectly connected to the bumper beam; providing a bulkhead for saidmotor vehicle, said bulkhead having a plurality of integrally formedattachment mounts; and attaching each of the second ends of the tubes toone of said plurality of integrally formed attachment mounts, in orderthat said crash energy absorption assembly is supported by said bulkheadof the motor vehicle.
 19. The method of claim 18, further comprising thestep of interconnecting the brackets with a cross tie.